The Difference Between a Rectal and an Oral Thermometer

All the mercury astronauts that went into space, they hand all their vital ines being sussed out the whole way through. They sort of had all these pads on them, monitoring their heart rates and stuff. But what i hadn't read before is they y also had a thermometer up the bum for their trips. A rectal thermometer will always have a round, bulbous tip,. An oral thermometer will have a longer, thin tip.